EN ISO 9239-1 "Determination of the burning behaviour of flooring products using a radiant heat source" is the test method of the Euroclass system for flooring products as defined in the Construction Products Regulation.
The imposed radiant flux simulates the thermal radiation levels likely to impinge on the floor of a corridor whose upper surfaces are heated by flames or hot gases or both, during the early stages of a developing fire in an adjacent room or compartment under wind-opposed flame-spread conditions.
The test method is applicable to all types of flooring, e.g. textile carpet, cork, wood, rubber and plastics coverings as well as coatings. Results obtained by this method reflect the performance of the flooring, including any substrate if used. Modifications of the backing, bonding to a substrate, underlay or other changes of the flooring may affect test results.
The horizontally oriented specimen is exposed to a radiant heat source, giving a heat flux gradient of approximately 11 kW/m2 at one end of the specimen, to less than 1 kW/m² at the other end. A line burner is situated at the high heat flux end of the specimen.
Smoke production is assessed by measuring attenuation of a light beam by smoke in the exhaust duct. The burning behaviour of the specimen is observed for flame spread. This flame spread is related to the CHF, the critical heat flux to extinguishment. This CHF is defined as the incident heat flux (kW/m²) at the surface of a specimen at the point where the flame ceases to advance and may subsequently go out. If after 30 minutes the specimen is still burning, the position of the flame front at this time is taken as the CHF.
The test samples shall be representative of the flooring in its end use. For a complete test series eight specimens (dimensions 1050 x 230) mm, four in one direction (e.g. production direction) and four in a direction perpendicular to the first direction are required. Including a chosen substrate (e.g. Euroclass A1 or A2 or wood based class Dfl supports) the overall flooring combination shall not become thicker than 40 mm.
The normal procedure is to first test one specimen in one direction and one specimen in the direction perpendicular to the first. The test which yields the lowest CHF value is repeated twice in that direction, so a total of at least four tests are required. If a product is not directional with regard to its fire behaviour only 3 tests (and four specimens) are required.
The test specimen is placed in a horizontal position below a gas-fired radiant panel inclined at 30° where it is exposed to a defined heat flux. A pilot flame is applied to the hotter end of the specimen.
Following ignition, any flame front which develops is noted and a record is made of the progression of the flame front horizontally along the length of the specimen in terms of the time it takes to spread to defined distances. If required, the smoke development during the test is recorded as the light transmission in the exhaust stack.
The results are expressed in terms of flame-spread distance versus time, the critical heat flux at extinguishment and smoke density versus time.
The test report contains information about the test specimens and test results.
The main test results are:
- CHF (the critical heat flux to extinguishment)
- The integral of the smoke obscuration over the testing time (expressed in % * minutes)